....You really can't say "Thats not Superman". That is indeed Superman. Maybe not the Superman you prefer. Maybe not the Superman of today, but the fact is that that is an official interpretation of the character. And one of the only reasons that Superman is gone is because DC softened all their characters in the 40's. Just because something has "evolved" (not really the word i'd use, but ok) from the original concept dosent mean the original concept is flawed or "not superman".

To me, Snyder using 38' Superman as a character template wouldnt be much different from burton using 39' Batman as a template for his films, or nolan using Batman # 1 Joker as a reference for ledger's performance.

Except Burton didn't use the 1939 interpretation of Batman. Otherwise he'd have been driving around in a Studabaker and flying around in an autogyro firing twin 45's like the Shadow.
Superman is not gone, just the opposite. Superman has one of the largest popculture presences of any intellectual property in history. You can't ignore the characters evolution to fit your tiny wishes and dreams. Yes i use the word evolution because that is what has happened. Evolution is a process of trail and error where an organism is changed in minor ways over a long period of time. Superman as a character isn't just what Siegel and Shuster started. Superman has been in the guding hands of hundreds of people, each adding their own part to the long narrative that is his story, that is evolution.